/*
This is a graph without a start node.
A start node is a node with no incoming edges
and one or more outgoing edges.
The start nodes are put at top of drawing.
But after cycle removal and reversing
few edges to break the cycle there is
a new start node. node 1 in this example.
*/
digraph "nos"
{
 1->2; // a cycle at 1->2->3
 2->3;
 3->1;
 3->4;
}
/* end. */
